The first part of the surveys were completed between June and September 2020 and focused on the urban Suze river and its Madretschkanal variant in Biel/Bienne. The second set of surveys were conducted between February 2021 and September 2021 and included a wider geographical scope around the municipality of Biel/Bienne. The objective was to construct an initial dataset on the remnant flowering plant populations growing in different green spaces around the city of Biel/Bienne and develop some standard reporting to make the data actionable for scientific and management purposes.
This chapter contains some overall summaries and a brief look into the invasive, redlist and priority species identified.
Around 700 plant surveys were conducted, resulting in the identification of some 6800 plant species, between June 2020 and September 2021. mostly focused on the urban Suze river and its Madretschkanal variant in Biel/Bienne. This chapter contains some background on the surveyor and provides a general summary of the data and the key indicators, such as invasive species identified.
In the medium term, the objective is to efficiently collect actionable data on vascular plant biodiversity in the municipality and through automation provide cost effective analysis and reporting to improve management and stakeholder engagement. As discussed in the introduction, it is up to local managers to manage local diversity and this project aims to be a tool in helping them to do so effectively.
The short term objective therefor was to immediately start constructing an actionable dataset on the vascular plants in public areas around the city of Biel/Bienne, with the knowledge that this dataset can be combined with longer term monitoring initatives conducted by Infoflora, as well as information the city has, for example its registry of city trees.
Currently enrolled as a master student at the Oeschger Center for Climate Change Research, I am using these surveys to gather data for my thesis work on plant populations. Previously trained as an economist these surveys also served as avenue to quickly developy my knowledge of the local flora through testing image based plant identification applications and using the Flora Helvetica guidebook.
In the first year, the focus was primarily on the urban Suze river and its Madretschkanal variant. Along this stretch of the river, as with many urban settings, there are many varied habitats, from deep shade to full pavement to flower strips maintained for ecological and aesthetic purposes. The sites are managed by the municipality to a greater or less degree and all areas surveyed were open access to the public and reasonably accessible for an average person. In 2021 the surveys included a wider geographic scope, but still largely remained in Biel and its environs. The zones surveyed ranged from railroad berms to green areas in the sidewalk in an effort to capture the diversity of herbaceous plants around the city.
The sites varied greatly in size and shape. The size of the sites was not recorded, but a detailed description of is available. In nearly all cases it is possible to recover the boundary of the sites based on the geometry of the object. For example, surveys were usually bounded by sidewalks, roads, or other barriers.
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Over the course of the two years 480 unique species were identified, the majority in the second year. Initially in June 2020, the number of plants that could be reliably identified by the surveyor was relatively small, where as by June 2021, the surveyor could reliably identify the common species that dominate the landscape. In year one, most observations (40%) were recorded in August, while in year 2 most observations were recorded in July, but that was only 20% of the total for that year. Some other changes between year one and year two to consider are the following:
The following tables provide some summary statistics.
Left: The number of unique species identifed, genus identified, and surveys per month. Right: Some summary statistics.
The vast majority of species identified were native, as can be seen from the following charts which decompose the species identified into native (rch & ns), non-native (ni), invasive (inv), and species identified only to the genus level (ongen). Despite a significant increase in the number of sites, the ratios remained relatively constant, aside from the growth of the "genus only" category in year 2.
At the same time, note that since this is only an identification study, these results do not indicate the relative biomass of native versus non-native species and a site may be dominated by a handful of species of either native or non-native origin. Note as well that indigenous species can acquire the attributes of a nonnative invasive species if it comes to dominate many habitats and reduce the overall biodiversity of areas due to its success.
This analysis follows the classification and definition of the IUCN Redlist as presented by Info Flora in classifying all species that arrived after 1500 (the discovery of America) as non-native. Thus any species that is on the IUCN redlist classification from Infoflora is considered native, any species left off is considered non-native. Given the limited timescale of interactions between these species and native ecological systems, they are still likely providing much fewer resources to insects and other taxa than native plants would be. While there are counter examples of this phenomenon, for example where non-native species provide a reservoir to threatened species, it is generally the case that nonnative species are less ecologically valuable. Aside from the quite small categories of "ns" which are non-native but culturally valuable as well as native species not included in the IUCN red list, (totally 5 observations or.08% of all species recorded) all species in this study fall neatly into the native / IUCN or non-native categories.
The vast majority of non-native plants are also not ivasive and most have no chance of establishing spontaneous populations in the wild or even in urban spaces. A good example of a common non native, non-invasive plant, classified as ni in the chart above, the annual Conyza canadensis (Erigeron canadensis) from Canada that thrives in disturbed areas around the city. It wsa identified in 12 locations in August and September 2021, however these numbers underplay the relative amount of the plant as it can seriously take over many areas as the below image illustrates. While the plant generally cedes its dominance as time passed ans thus is not considered invasive, it can still dominate areas during the succession phase. Another two examples of this category are Onobrychis viciifolia, common in fields and along road verges in late spring and early summer, and Eupatorium cannabinum, common along road verges and river banks.
As the below linechart shows, the number of unique non native and non invasive species identified peaked in April and May 2021.
Of the non-native species a small percentage are actually considered invasive. In order to be considered invasive they must be able to reproduce in the wild and pose a threat to humans and the ecosystems. Info Flora maintains a list of the current watch list and black list species, a number of which were identified over the course of the survey. Some of them were purposefully introduced in a bygone era, such as the Mahonia aquifolium, which is planted throughout the Madretsch quarter in Biel/Bienne. Others have moved into empty lots of their own accord such as Solidago canadensis and Erigeron Annuus.
The following charts presents the blacklist (BL) and watchlist (WL) species identified per month in year 1 and year 2. The charts follow the overall pattern of survey, peaking in the same month as when the overall number of surveys peaked, namely in August for year 1 and in June-July for year 2. There is a significant increase in the number of invasive species identified from May to June that is greater than the increase in surveys conducted over this period.
The number of unique invasive species identified on the blacklist and Watchlist rose from one species each identified in February, March and April to a high of 7 spcies and 4 species respectively, in July. To a certain extent this is due to counting plants in flower - some early populations of Erigeron annuus were found and a few scattered Mahonia aquifolium begain to flower in March and April.
The IUCN Red List is an internationally comparable ranking of the conservation status of individual species and biotopes. Infoflora worked with the IUCN to create a national redlist for Switzerland, last updated in 2016. This analysis was complemented in 2019 with the publishin of regional redlist data. This regional redlist data, categorized according to biogeographical regions, is what is used in this section. Switzerland is divided into six biogeographical regions, and Biel/Bienne is located in the Middle Plateau / Central Plateau. For the analysis here, I used the regional redlist data for the central plateau and only included observations within the central plateau, which is still the vast majority of survey locations and species identified - about 7000 of the 7500 observations.
The below chart demonstrates the key point that most species found are classified as "Least Concern" (LC), which was easy to predict. The species themselves are widespread (hence the categorization of LC) and the surveys were conducted in disturbed, urban environments where one might be unlikely to find rare species.
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The surveys will be repeated in year 3. Given the surveyor's additional experience with the subject matter, it is expected to collect significantly more observations and to continue to improve accuracy, efficiency, and geographic coverage. This increased data will also be relatively easier thanks to experience working with the data and having prewritten useful code for its analysis and visualization.
The objective of year three is to build the predictive capacity of the data set to answer the following questions: Given the list of vascular plant species that occur in this area and this set of environmental data, what can I predict about the supported biodiversity ? What areas are most important for target species (bees/butterflies) throughout the year ?
This will require collecting plant occurence data on a wide array of habitats throughout the year and integrating this data into a format compatible for analysis with satellite and GIS data from the municipalaity. In additon
Surveys will be conducted from late February through October 2022. This is to capture the early and late blooming flowers that are especially important for hibernating insect species. Ideally each location will be surveyed on a bi-monthly basis to capture the seasonality of the flowering populations, but this will likely not be a possible schedule to maintain for all observation. Thus, a core group of locations will receive this treatment, while other locations will be surveyed opportunistically with the aim of establishing a solid coverage of the municipality of Biel/Bienne.
The surveys will again be focused on Biel and the immediate surrounding periurban region. The same locations will be surveyed as in 2021. There are some differences between year 2 and year 3:
The surveys will be conducted using the infoflora app on an android smartphone (Samsung A51). Surveys will again be focused on identification of species and not an estimation of ground cover or dominance. The following differences will be registered:
A major focus of year three is the compatibility of this data set with the needs of the municipal, cantonal and federal managers of green spaces and biodiversity. As such, a more active approach to the integration of data from Infoflora, the municipality of Biel/Bienna and surrounding communes. In addition, in order to investigate the results of interventions that have taken place over the years, data will be sought out on renaturalization projects to attempt to identify outcomes.